on ONE machine out of 30 odd, if i restart the machine, everything works fine, but after a while, we can't submit, the shell flashes up, but the main window doesn't appear... there is a process for it in task manager, but no submitter

then if i try and re-install RR, the installer won't launch (same thing, shell flashes up, no main window)

I think the easiest is to check it via a remote session.
Please use www.RoyalRender.de/support to open a ticket, then I can send you instructions for a remote session._________________Holger SchÃ¶nberger
Binary Alchemy - digital materialization